Title:
Corrosion Behavior of Steel Rebar in Graphene Oxide Modified Fly Ash-Based Geopolymer Concrete
Author(s):
Shi
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
4/2/2023
Abstract:
Geopolymer composites have increasingly demonstrated comparable or better engineering properties or performance relative to their portland-cement-based counterparts; yet the studies of rebar corrosion behavior in geopolymer concrete remain limited. A patented technology by Washington State University has demonstrated the feasibility of diverting Class C fly ash from waste stream to beneficial use in concrete, entailing the use of chemical activators (e.g., waterglass and free lime) and trace amount of a novel 2D nanomaterial, graphene oxide (GO). In this study, four cementitious binders (ordinary portland cement, GO-modified cement, fly ash-based geopolymer, and GO-modified fly ash-based geopolymer) were selected to evaluate the corrosion behavior of carbon steel rebar in concrete. To accelerate the initiation of rebar corrosion, the concrete samples were subjected to rapid freeze/thaw cycles to produce a reasonable level of cracking. Subsequently, the open circuit potential, polarization resistance, and electrochemical impedance spectroscopy of each group of concrete samples ponded in 10 wt.% NaCl were periodically monitored and compared. For selected samples, microscopic investigations (e.g., scanning electron microscopy, thermogravimetric analysis, and X-ray diffraction) were conducted to elucidate the interfacial interactions between rebar and different concrete matrices.